Switzerland glaciers are set to reach “Glacier Loss Day” on June 29, marking the point when all seasonal snow has melted and any further melting directly reduces glacier ice. Scientists say the early arrival of this milestone reflects another difficult year for the country’s glaciers driven by low winter snowfall, Saharan dust deposits and an intense early summer heatwave.
According to researchers at ETH Zurich and the Swiss Glacier Monitoring Network (GLAMOS), glaciers have been melting at nearly twice the average rate recorded between 2010 and 2020. The current pace of melting is approaching the record levels observed during the extreme summer of 2022, when glaciers lost around 6% of their total mass in a single year.
Heatwaves and Low Snowfall Speed Up Glacier Melting
This year began with unusually low snow accumulation across many Swiss glaciers, leaving them with little protection against rising temperatures. Dust blown from the Sahara during spring darkened the snow surface, allowing it to absorb more sunlight and melt even faster.
Scientists explain that once Glacier Loss Day arrives, every additional litre of meltwater comes directly from glacier ice rather than seasonal snow, permanently reducing glacier size. In 2022, Glacier Loss Day occurred even earlier on June 26 during Switzerland’s warmest year on record.
Shrinking Glaciers Threaten Future Water Supplies
Although rapid melting temporarily increases the amount of freshwater flowing into rivers, researchers warn that this benefit will not last. A recent study found that despite greater ice loss in 2022 compared with the extreme heatwave of 2003, glaciers actually released less meltwater because they had already lost significant amounts of ice over previous decades.
Since 2003, Switzerland has lost around 200 square kilometres of glacier ice an area nearly the size of the canton of Zug. Scientists warn that as glaciers continue shrinking, they will eventually be unable to provide enough meltwater during hot, dry summers, increasing pressure on freshwater resources, ecosystems and hydropower generation.
Researchers say the current trend highlights the growing impact of climate change on Alpine glaciers and underscores the need for continued monitoring as glacier retreat accelerates across the region.